The present invention relates to an outdoor sauna which applies Chomseongdae observatory which has a relatively smaller space than the lower floor of the sauna. Therefore, the present invention which is a sauna (1) has: a lower floor sauna (10) which includes a lower floor entrance door (11) and a smoke discharge unit (12) which has a smoke pipe； and an upper floor sauna (20) which includes an upper floor entrance door (22) which is connected to stairs (21) and windows (23) in the upper part of the lower floor sauna (10) in all directions. The sauna includes: a heat radiation means (30) which radiates heat energy to the internal wall (24) of the upper floor sauna (20) by being heated by receiving the heat energy of the lower floor sauna (10) in the central part of the upper floor sauna (20)； a perspective means (40) which enable the outside to be seen through while blocking heat energy from being radiated from the upper part of the upper floor sauna (20)； and a stay means (50) which is connected to the upper floor entrance door (22) and is installed to be fixated on the outer edge of a sauna frame (2). Therefore, a fresher vapor bath is possible since: the vapor bath can be performed in the upper floor sauna (20) by heating the internal wall (24) of the upper floor sauna (20) at a high temperature by heating the heat radiation means (30) in order to make the internal wall hot by heat energy which heats the lower floor sauna (10)； and a user does not have the feeling of stuffiness by seeing sky through the perspective means (40) in the upper floor sauna (20). The stay means (50) enables the vapor bath to be fresher and convenient by quickly cooling down a body without moving to the lower floor again after taking the vapor bath in the upper floor sauna (20).이 발명은 하층 한증실 보다 상대적으로 작은 공간을 가지게 되는 첨성대를 응용한 야외용 한증막에 관한 것이다.따라서, 본 발명은 하층출입문(11)과 연통(13)이 있는 연기배출부(12)를 구비하는 하층 한증실(10)과, 상기 하층 한증실(10) 상부에 계단(21)과 연결되는 상층출입문(22)과 사방으로 창문(23)을 구비하는 상층 한증실(20)이 있는 한증막(1)에 있어서, 상
